public class interfacer{
    private static Singleton instance=null;
    private Singleton(){}
    public static synchronized Singleton getInstance(){
        if(instance==null){
            instance=new Singleton();r
        }
        return instance;
    }
}
class Singleton{
    private static Singleton instance=null;
    private Singleton(){}
    public static synchronized Singleton getInstance(){
        if(instance==null){
            instance=new Singleton();
        }
        return instance;
    }
}
